	AREA Irq, CODE,READONLY
	CODE32
	EXPORT irqhandler
	IMPORT do_irq
	
irqhandler
	SUB LR,LR,#4	;very importance
	STMFD R13!,{R0-R12,LR} ;prevent interupt qiantao
	MRS R4,SPSR
	STMFD R13!,{R4}
	
	BL do_irq
	
	LDMFD R13!,{R4}
	MSR SPSR_cxsf,R4
	LDMFD R13!,{R0-R12,PC}^
	
	END